B3873
DTC B3873
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle (Diagnostic System Check - Vehicle) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Strategy Based Diagnosis) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Diagnostic Procedure Instructions) provides an overview of each diagnostic category.
DTC Descriptors
DTC B3873 01
- Front Washer Relay Circuit Short to Battery
DTC B3873 02
- Front Washer Relay Circuit Short to Ground
DTC B3873 04
- Front Washer Relay Circuit Open
Diagnostic Fault Information
Circuit/System Description
The body control module (BCM) controls the windshield washer fluid pump based on an input from the turn signal/multifunction switch. The BCM monitors the washer switch through the windshield washer switch signal circuit. When the wash switch is closed, ground is supplied to the front washer switch signal circuit. When this is the case, the BCM will command the windshield washer fluid pump and the low speed wipers on.
Conditions for Running the DTC
* Ignition ON.
* A washer request is present.
* The system voltage is between 9-16 V.
Conditions for Setting the DTC
* A short to ground or an open/high resistance is detected in the windshield washer relay control circuit.
* A short to voltage is detected in the windshield washer relay control circuit.
Action Taken When the DTC Sets
Washer operation is suspended.
Conditions for Clearing the DTC
* A current DTC clears when the diagnostic runs and passes.
* A history DTC will clear after 50 consecutive ignition cycles without a fault present.
Reference Information
Schematic Reference
Wiper/Washer Schematics (Electrical Diagrams)
Connector End View Reference
Component Connector End Views (Connector End Views By Name)
Description and Operation
Wiper/Washer System Description and Operation (Description and Operation)
Electrical Information Reference
* Circuit Testing (Circuit Testing)
* Connector Repairs (Connector Repairs)
* Testing for Intermittent Conditions and Poor Connections (Testing For Intermittent Conditions and Poor Connections)
* Wiring Repairs (Wiring Repairs)
Scan Tool Reference
Control Module References (Programming and Relearning) for diagnostic tester information.
Circuit/System Verification
Operate the front washer by using the S80 Window Wiper/Washer Switch. Verify the G24 Windshield Washer Pump activates.
Circuit/System Testing
1. Ignition OFF, disconnect the harness connector X2 at the X50A Fuse Block - Underhood.
2. Disconnect the harness connector X4 at the K9 Body Control Module.
3. Test for less than 5 ohm between the control circuit terminal 21 X2 at the X50A Fuse Block - Underhood and the signal circuit terminal 14 X4 at the K9 Body Control Module.
• If the value is not within the specified range, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, test or replace the K9 Body Control Module.
4. Test for infinite resistance between the control circuit terminal 21 X2 at the X50A Fuse Block - Underhood and ground.
• If the value is not within the specified range, test the control circuit for a short to ground.
5. If all circuits test normal, test or replace the X50A Fuse Block - Underhood.
Component Testing
Relay Test
1. Ignition OFF, disconnect the harness connector X1 at the X50A Fuse Block - Underhood.
2. Test for 60-200 ohm between control circuit terminal 21 X2 and ground circuit terminal 71 X1.
• If all circuits test normal, test or replace the X50A Fuse Block - Underhood.
Output Control Tests
Ignition ON, command the Windshield Washer Relay Command ON and OFF with a scan tool. Observe that the KR11 Windshield Washer Pump Relay clicks and the G24 Windshield Washer Pump runs.
If the KR11 Windshield Washer Pump Relay does not work, replace the X50A Fuse Block - Underhood.
If the KR11 Windshield Washer Pump Relay works, but the G24 Windshield Washer Pump does not run, test the washer fluid pump control circuit and the washer fluid pump ground circuit.
If all circuits test normal, replace the G24 Windshield Washer Pump.
Repair Instructions
Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.
* Control Module References (Programming and Relearning) for BCM replacement, setup, and programming
* Windshield Washer Pump Replacement (Windshield Washer Pump Replacement)